Electrically operated automatic resetting circuit breaker mechanisms



Nov. 14, 1961 Filed Sept. 8, 1958 W. W. POULTON, JR ELECTRICALLYOPERATED AUTOMATIC RESETTING CIRCUIT BREAKER MECHANISMS 3 Sheets-Sheet 1:==-=r 0, 5 420x50 INVENTOR.

Mayan/m flJdzra/y-M? Nov. 14, 1961 w. N, JR 3,009,087

ELECTRICALLY OPERATED AUTOMATIC RESETTING CIRCUIT BREAKER MECHANISMSFiled Sept. 8, 1958 5 Sheets-Sheet 2 1961 w. w. POULTON, JR 3,009,087

ELECTRICALLY OPERATED AUTOMATIC RESETTING CIRCUIT BREAKER MECHANISMSFiled Sept. 8, 1958 v 3 Sheets-Sheet 3 INV ENT OR. 50/1 JO/V 41 701A 704 MM M United States Patent 3 009,087 ELECTRICALLY OPER ATED AUTOMATICRESET- TING CIRCUIT BREAKER MECHANISMS Wilson Ward Poulton, In,Broomall, Pa., assignor to I-T-E Circuit Breaker Company, Philadelphia,Pa., a

corporation of Pennsylvania Filed Sept. 8, 1958, Ser. No. 759,718 10Claims. (Cl. 318-2) The instant invention relates generally toelectrically powered mechanisms for the operation of circuit breakersand more particularly to a mechanism of this type which includesprovisions for automatic resetting of the circuit breaker after it hasbeen tripped open. Many circuit breakers, as exemplified by the moldedcase breaker described in the copending application of AugustBodenschatz entitled Hold-Open and Anti-Rebound Latches, Serial No.734,785, filed May 12, 1958, now US. Patent No. 2,932,706, and assignedto the assignee of the instant invention, include an operating mechanismwhich must be reset to effect a closing which follows the automatictripping of the circuit breaker.

Prior art devices which include electrically operated automaticresetting mechanisms require the removal and replacement of the circuitbreaker handle and the addition of an auxiliary switch mounted in theinterior of the circuit breaker in order to achieve automatic reset.These prior art mechanisms usually require critical adjustments sincethey utilize a unidirectional motor and a rotary switch to limit motortravel. Further, operation of these devices is awkward, time consumingand dangerous.

When the circuit breaker is operated by hand to the open position, theautomatic reset switch closes, which automatically energizes the motorthereby operating the lever to the OE position and in so doingjeopardizes the safety of the operation. In addition, the mechanism,utilizing a unidirectional motor in conjunction with a rotary switch forlimiting motor travel, can continuously run when operated by hand.

The device of the instant invention provide a torque sensitive device inwhich power is transmitted from the motor through a clutching mechanismto a breaker cam which operates the breaker handle. In a firstembodiment of my invention the clutching mechanism comprises a pair ofshoes engageable with a drum with the shoes being spring loaded to slipat a torque slightly above that required to operate the breaker handleto the Reset and On positions. This permits the mechanism to benon-critical to handle position.

As the circuit breaker handle reaches the end of its stroke, therotational force of the motor exceeds the break-away torque of the shoesthereby causing the shoes to slip with respect to the drum. When themechanism reaches the end of its travel either in the On or Resetpositions of the circuit breaker, the shoes absorb the inertia of thebrake drum without damage to the circuit breaker handle or contactoperating mechanism.

Automatic reset is accomplished by utilizing a normally closed switchwhich is engaged by the circuit breaker handle when the circuit breakeris closed and when so engaged, the switch is opened. A second switch,operated by the circuit breaker cam as it nears the end of its traveltoward either the Closed or Reset positions, is utilized to conditionthe operating motor for rotation in forward or reverse directions inwhich the cam will operate the circuit breaker handle toward the Resetand Closed positions respectively. That is, when the circuit breakerhandle nears the Reset position, the second switch conditions the motorfor rotation in the reverse direction and when the operating handleapproaches the On position, the second switch conditions the motor forforward operation.

ice

When the motor is conditioned for forward operation and the first switchis closed, the motor will automatically operate the circuit breakerhandle to the reset position when the circuit breaker is tripped.

The circuit breaker cam includes a pair of spaced rollers which engagethe circuit breaker handle. With the circuit breaker closed, the handleis positioned toward the roller which was not utilized to move thehandle to the closed position by the action of the circuit breakertoggle mechanism. If the circuit breaker is tripped the toggle mechanismtends to move the circuit breaker handle to a tripped position which isat a point between the On and Olf positions. This movement is suflicientto cause disengagement of the circuit breaker handle from the firstswitch thereby energizing the motor in a forward direction to operatethe circuit breaker handle to the Reset position.

Prior to the arrival of the circuit breaker at the Reset position, thesecond switch will be operated to condition the motor for rotation inthe reverse direction. However, the inertia of the mechanism issufiicient to drive the circuit breaker handle to the Reset position.

With the motor conditioned for reverse rotation, depressing an Oncontrol button will energize the motor for rotation in the reversedirection which will cause the circuit breaker cam to move the handletoward the On position. Prior to the arrival of the handle at the Onposition the contacts of the circuit breaker will have become engagedand the toggle mechanism will cause the handle to move faster than thecam which is driving the handle toward the On position. Thereafter, thecam will operate the second switch so that the motor is conditioned forrotation in the forward direction. After the second switch is operated,the inertia of the mechanism will cause continued rotation of thecircuit breaker cam until it strikes a positive stop which usuallycomprises the housing of the mechanism where the torque on the mechanismwill exceed the break-away torque of the shoes and the mechanism willcome to a halt. The fact that the second switch is thrown before theends of the closing and reset strokes eliminates the problem of criticalswitch positioning.

Hand operation is accomplished by disengaging the motor from the brakedrum. This is readily accomplished by utilizing a polygonal nut totransmit power from the motor to the brake drum with the nut beingbiased upwardly toward the motor. The polygonal nut is depressible intothe brake drum by means of a sleeve and, when so depressed, the drum isdisconnected from the motor thereby allowing hand operation. A'noncircular member or a splined circular member may be utilized as theequivalent of the polygonal nut.

The second embodiment of my invention utilizes a plurality of rollers inconjunction with a groove drum as the slip coupling means. With therollers disposed within the grooves, there is a positive drivingconnection between the drum and the circuit breaker cam. However, therollers are all biased toward the center of the drum so that when thecircuit breaker operating handle reaches the Reset and On positions thebiasing force is overcome and the rollers are driven from the grooves toride on the periphery of the drum thereby severing the drivingconnection.

Since the mechanism of the instant invention includes a torque limitingdevice, it has the advantage of permitting infinite over travel of thedriving means. Thus an extremely high speed motor, with its accompanyinghigh inertia, may be utilized to achieve short time switching.

The construction of the mechanism is such that it may be mounted to acircuit breaker as a complete unit by merely utilizing two or moremounting studs secured to 3 the breaker and securing electrical leads toan enclosed terminal block. There is no need to modify the circuitbreaker handle or secure any attachments thereto. Further, the mechanismdoes not require any critical adjustment when the mechanism istransferred from one breaker to another.

Accordingly, a primary object of the instant invention is to provide anovel electrically powered mechanism for the operation of a circuitbreaker.

Another object is to provide a novel electrically powered mechanismwhich utilizes a torque limiting device comprising a coupling meanswhich slips whenever the torque required to operate the mechanismexceeds a predetermined value.

A further object is to provide a novel electrically powered mechanismhaving means for the selective manual operation thereof.

A still further object is to provide an electrically powered mechanism,for the operation of circuit breakers, which may be secured to thecircuit breaker as a unitary structure.

These as well as other objects of the instant invention shall becomereadily apparent after reading the following description of theaccompanying drawings in which:

FIGURE 1 is a side elevation of a first embodiment of my novel mechanismshown mounted to a molded case circuit breaker.

FIGURE 2 is a plan view of the mechanism of FIG- URE 1.

FIGURE 3 is a cross-section taken through line 33 of FIGURE 2 looking inthe direction of the arrows 33.

FIGURES 4 and 5 are cross-sections taken through line 4-4 of FIGURE 3looking in the direction of the arrows 4- 4. In FIGURE 4 the circuitbreaker handle is illustrated in the On position and in FIGURE 5 thecircuit breaker handle is illustrated as being in the Reset position.

FIGURE 6 is a schematic diagram illustrating the electrical connectionsnecessary to achieve automatic resetting.

FIGURE 7 is a cross-sectioned figure similar to FIG- URES 4 and 5illustrating a second embodiment of my invention.

Now referring more particularly to FIGURES 1-6, mechanism 10 is securedto circuit breaker 11 by means of studs 12 which extend from circuitbreaker 11 through openings in the bottom surface 14 of housing 15 andare engaged by nuts 13. The bottom surface 14 is bowed in the region 16thereby creating a pressure at the opposite end 17 of surface 14 againstthe top of the circuit breaker housing to achieve a firm seating ofmechanism 10 upon circuit breaker 11.

Mechanism 10 comprises a motor 20 which drives gear train 21 whoseoutput shaft 22 drives pinion 23. The teeth of pinion 23 are in meshwith the teeth of drive gear 24 which is rotatably mounted about sleeve25. Shaft 26 is mounted within sleeve with one end 27 thereof beingpositioned within bearing opening 28 of block 29. An extension 30, theouter edge of which is impinged, extends from block 29 through anopening in bottom surface 14 thereby securing block 29 to housing '15.

End 27 of shaft 26 is provided with a pair of flat opposed surfacesentered into complementary shaped opening 31 of cam 32. Spring retainer33 engages shaft end 27 thereby securing shaft 26 to cam 32 for rotationin unison therewith.

Drum 34 is positioned adjacent to the top surface of cam 32 and isarranged coaxially with shaft 26. Coil spring 35 is disposed about shaft26 in the region of brake drum '34. Drum 34 is provided with a squareshaft opening 37 at the center thereof. Polygonal nut 36, in the shapeof a square, is disposed within opening 37 and is biased upwardly bycoil spring 35 toward engagement with drive gear 24 which is alsoprovided with a square opening 38. The bottom surface 39 of sleeve 25 ispositioned adjacent to the top of nut 36. A pointer 40 is rigidlysecured to shaft 26 by means of screw 41 and provides an externalindication of the angular position of cam 32. Spacer 42 is disposedwithin sleeve opening 43 to provide clearance between pointer 40 andsleeve 25 as shaft 26 rotates.

Arms 50 and 51, formed of structural sections, are pivotally mounted at52, 53, respectively, to cam 32. Shoes 5-4, 55, including frictionlinings 56, 57, respectively, are pivotally mounted at 58, 59 near oneof the ends of the arms 50, 5 1, respectively. The other ends of arms56, 51 are interconnected by members 60, 61, respectively, which arepivoted at 62, 63, respectively. Member 60 engages a pin 64 which isdisposed within a central opening 65 of member 61. A compression spring66 is disposed about member 61 and is positioned to urge members 60 and61 away from each other. Thus, spring 66 urges linings 56, 57 againstthe peripheral surface of drum 34.

Rollers 67, 68 are pivotally mounted to cam 32 in spaced apartrelationship forming gap 69 therebetween. Circuit breaker operatinghandle 70 extends through opening 70a in the bottom surface 14 ofhousing 15 to be disposed within gap 69 and when operated to its Onposition (FIGURE 4) will engage switch 71 secured to housing 15 by meansof bracket 72. Another switch 73 is secured to the bottom surface 14 ofhousing 15 and is positioned for operation by means of pins 74 and 75which project downwardly from cam 32.

It is to be noted that when the circuit breaker handle 70 is in the Onposition of FIGURE 4 there is a substantial gap between handle 70 androller 67. Thus, when circuit breaker 11 is automatically tripped due tothe occurrence of a fault current, the spring loaded toggle mechanism ofcircuit breaker 11 will move handle 70 against roller 67, as indicatedin phantom in FIGURE 4. In this position, handle 70 is disengaged fromswitch 71 so that the switch 71 is now in the closed position.

Motor 20 is of a universal type having a field winding 77 for rotationof the motor 20 in a reverse direction. By depressing On control 78 withswitch 73 thrown to the dotted line position of FIGURE 6, motor 20 willrotate in a forward direction so as to rotate drive gear 24counterclockwise with respect to FIGURE 5.

At this time, nut 36 is disposed within opening 38 so as to form adriving connection between drive gear 24 and drum 34. Linings 56, 57 inengagement with drum 34 form a driving connection which, acting throughpins 52 and 53, transmits a counterclockwise rotation to cam 32 therebymoving rollers 67, 68 counterclockwise about shaft 26. Thus, roller 67engages handle 70 to move handle 70 from the Reset position of FIGURE 5toward the On position of FIGURE 4.

At the point where the toggle mechanism of circuit breaker 11 crossesover center to rapidly move the cooperating contacts (not shown) ofcircuit breaker 11 into engagement, handle 70 moves away from roller 67to- Ward roller 68. Cam 32 will continue to move counterclockwise untilthe inertia energy, of motor 20 and the elements of gear box 21, hasbeen spent or until such time as surface 79 of cam 32 strikes the wall80 of housing 15. Under the latter circumstances the force required torotate cam 32 in the clockwise direction exceeds the break-away torqueof the coupling mechanism, comprising drum 34 and shoes 54, 55, therebycausing the coupling mechanism to slide without damage to the closingmechanism 10 or circuit breaker 11.

In moving from the Reset position of FIGURE 5 to the On position ofFIGURE 4 pin 74, carried by cam 32, has engaged arm 82 of switch 73thereby throwing switch 73 to the solid line position illustrated inFIG- URE 6. In this position of switch 73, motor 20 is conditioned forrotation in the reverse direction and cannot be operated in the forwarddirection by depressing the On control 78. That is, upon the closing ofautomatic reset switch 71 or the closing of Off control 83, winding 76will be energized so as to cause rotation of motor 20 in a directionsuch that drive gear 24 will rotate clockwise with respect to FIGURE 4.If the mechanism is in the On position of FIGURE 4, depressing switch 83will cause motor 20 to operate cam 32 clockwise about shaft 26 withroller 68 engaging handle 70 to operate the circuit breaker to the Resetposition of FIGURE 5.

Since contacts 84 of automatic reset switch 71 are connected in parallelwith Off switch 83, as soon as handle 70 has become disengaged fromswitch 71, mechanism will continue to move handle 70 to the Resetposition even though Off switch 83 is released before handle 70 hasreached the Reset position. Before handle 70 has reached the Resetposition, pin 75 will have engaged arm 82 of switch 73 thereby throwingswitch 73 to the dotted line position of FIGURE 6 to deenergize winding77 and condition motor for the rotation in the forward direction. Thisoperation of switch 73 usually takes place before handle 70 has beendriven to the reset position by roller 68. However, the inertia energyof motor 20 and the elements of gear box 21 is sufiicient to causecontinued rotation of drive gear 24 so as tomove handle 70 completely tothe Reset position, with the torque limiting features of the clutchingmechanism 34, 54, 55 preventing any damage to handle 70 as well as otherelements of the circuit breaker mechanism 11. Automatic resetting takesplace in a similar manner. That is, when circuit breaker 11 is openeddue to an overload condition, the toggle mechanism thereof will causehandle 70 to move from the solid line position of FIGURE 4 to thephantom position of FIGURE 4 thereby perrnitting the contacts 84 ofautomatic reset switch 71 to move to the closed position. Since switch73 is in the solid line position of FIGURE 6, motor 20 is conditionedfor operation in the reverse direction. Thus, when contacts 84 areclosed, winding 76 is energized and mechanism 10 will operate handle 70to the reset position of FIGURE 5.

The upper end 44 of sleeve 25 is usually positioned above the upper end45 of shaft 26, which is of a square cross-section and reduced in sizefrom the central portion of shaft 26. Manual operating crank 46 includesa transverse head 47 at one end thereof which is provided with a recesshaving a circular portion 48 of approximately the same diameter assleeve 25 and a square portion 49 of approximately the same size as theend portion 45 of shaft 26. By mounting head 47 on sleeve 25, sleeve 25may be depressed to move nut 36 downward against the force of spring 35thereby disengaging nut 36 from drive gear 24.

The upper portion 85 of nut 36 is tapered as is the bottom portion ofopening 38 thereby facilitating the disengagement of nut 36 from drivegear 24. Simultaneously, the square end portion 45 of shaft 26- willnest in recess 49 so that a rotation of crank 46 will cause acorresponding rotation of cam 32. Thus, when sleeve 25 is depressed amanual rotation of shaft 26 by crank 46 will cause the rotation of cam32 about shaft 26 as a center to effectuate the operation of a circuitbreaker handle 70. Even though motor 20 should be energized at thistime, the rotation drive gear 24 will not be transmitted to drum 34since nut 36 is-disengaged from drive gear 24. Thus, the operator willnot be injured by an accidental energization of motor 20 while he isattempting a manual operation of the mechanism.

Whenhandle 46 is removed from the remainder of the mechanism 10, spring35 will force nut 36 upwardly toward drive gear--24.- At this time,opening 38 of drive gear 24 may not be in the correct angular positionto receive nut 36. However, upon energization of motor 20 and rotationof drive gear 24, spring 35 will force nut 36 to enter opening 38 whenopening 38 and nut 36 are in corresponding angular positions therebyonce again establishing the driving connection between motor 20 and drum34.

Lamps 91-93 (FIGURE 6) provide an indication of the condition of circuitbreaker 11, that is, if lamp 91 is lighted circuit breaker 11 is On, iflamp 92 is lighted circuit breaker 11 has been tripped, and if lamp 93is lighted circuit breaker 11 has been operated to the Off position.

The mechanism of FIGURE 7 is identical to that of mechanism 10 exceptfor the clutching means. Accordingly, for the sake of brevity andclarity the same reference numbers have been utilized to identifyidentical elements.

The clutching means of mechanism 100 comprises drum 101 having equallyspaced depressions 102105 in the periphery thereof. Rollers 106-107pivotally secured to shoe 54 and rollers 108, 109 pivotally secured toshoe 55 are adapted to nest in depressions 102105.

With rollers 106109 nested in depressions 102105 a driving connectionexists between drum 101 and cam 32. When the torque required to drivecam 32 exceeds the torque supplied by spring rollers 106109 will beforced out of depressions 106 to ride on the periphery 110 of drum 101.In this position the driving connection between drum 101 and cam 32 isbroken without damage to mechanism 100 of circuit breaker 11.

Since a definite outward radial movement of shoes 54 and 55 is requiredto effect disengagement of the driving connection between drum 101 andcam 32 this movement may be utilized to actuate switches (not shown) forconditioning the motor for halting motor rotation in one direction andconditioning the motor for rotation in the opposite direction. This typeof arrangement may be utilized in place of the long stroke toggle switch73 and is especially useful for slow speed operation wherein the inertiaenergy of the driving means is at a low level.

Accordingly, I prefer to be bound not by the specific disclosureherewith but only by the appending claims.

I claim:

1. A mechanism for the operation of a circuit breaker manual operatinghandle; said mechanism comprising a driving means, a cam, and a couplingmeans; said coupling means forming a first driving connection betweensaid cam and said driving means; said cam being operatively positionedto engage a circuit breaker operating handle; said coupling means beingconstructed to slip when the torque required to drive said cam exceeds apredetermined value; said cam including a first portion and a secondportion spaced from said first portion to form a gap therebetween; saidmechanism being adapted for mounting to a circuit breaker with theoperating handle of the circuit breaker being positioned within saidgap; a second driving connection interposed between said driving meansand said first driving connection; said second driving means beingselectively disengageable and when disengaged permitting manualoperation of the circuit breaker; said second driving means whendisengaged preventing said driving means from operating the circuitbreaker; said circuit breaker handle being movable between a first and asecond position; said mechanism also including a normally closed firstswitch operatively positioned for engagement by said handle when saidhandle is in said first position; said switch being open when engaged bysaid handle.

2. A mechanism for the operation of a circuit breaker manual operatinghandle; said mechanism comprising a driving means, a cam, and acoup-ling means; said coupling means forming a first driving connectionbetween said cam and said driving means; said cam being operativelypositioned to engage a circuit breaker operating handle; said couplingmeans being constructed to slip when the torque required to drive saidcam exceeds a predetermined value; said cam including a first portionand a second portion spaced from said first portion to form a gaptherebetween; said mechanism being adapted for mounting to a circuitbreaker with the operating handle of the circuit breaker beingpositioned within said gap; a second driving connection interposedbetween said driving means and said first driving connection; saidsecond driving means being selectively disengageable and when disengagedpermitting manual operation of the circuit breaker; said second drivingmeans when disengaged preventing said driving means from operating thecircuit breaker; said circuit breaker handle being movable between afirst and a second position; said mechanism also including a normallyclosed first switch operatively positioned for engagement by said handlewhen said handle is in said first position; said switch being open whenengaged by said handle; a second switch having a third and a fourthposition; said driving means being conditioned for operation in aforward direction to move said handle to said first position when saidsecond switch is in said third position and being conditioned foroperation in a reverse direction to move said handle to said secondposition when said second switch is in said fourth position.

3. A mechanism for the operation of a circuit breaker manual operatinghandle; said mechanism comprising a driving means, a cam, and a couplingmeans; said coupling means forming a first driving connection betweensaid cam and said driving means; said cam being operatively positionedto engage a circuit breaker operating handle; said coupling means beingconstructed to slip when the torque required to drive said cam exceeds apredetermined value; said cam including a first portion and a secondportion spaced from said first portion to form a gap therebetween; saidmechanism being adapted for mounting to a circuit breaker with theoperating handle of the circuit breaker being positioned within saidgap; a second driving connection interposed between said driving meansand said first driving connection; said second driving means beingselectively disengageable and when disengaged permitting manualoperation of the circuit breaker; said second driving means whendisengaged preventing said driving means from operating the circuitbreaker; said circuit breaker handle being movable between a first and asecond position; said mechanism also including a normally closed firstswitch operatively positioned for engagement by said handle when saidhandle is in said first position; said switch being open when engaged bysaid handle; a second switch having a third and a fourth position; saiddriving means being conditioned for operation in a forward direction tomove said handle to said first position when said second switch is insaid third position and being conditioned for operation in a reversedirection to move said handle to said second position when said secondswitch is in said fourth position; a first control efiective to actuatesaid driving means when said second switch is in said third position; asecond control effective to actuate said driving means when said secondswitch is in said fourth position.

4. A mechanism for the operation of a circuit breaker manual operatinghandle; said mechanism comprising a driving means, a cam, and a couplingmeans; said coupling means forming a first driving connection betweensaid cam and said driving means; said cam being operatively positionedto engage a circuit breaker operating handle; said coupling means beingconstructed to slip when the torque required to drive said cam exceeds apredetermined value; said cam including a first portion and a secondportion spaced from said first portion to form a gap therebetween; saidmechanism being adapted for mounting to a circuit breaker with theoperating handle of the circuit breaker being positioned within saidgap; a second driving connection interposed between said driving meansand said first driving connection; said second driving means beingselectively disengageable and when dis engaged permitting manualoperation of the circuit breaker; said second driving means whendisengaged preventing said driving means from operating the circuitbreaker;

said circuit breaker handle being movable between a first and a secondposition; said mechanism also including a normally closed first switchoperatively positioned for engagement by said handle when said handle isin said first position; said switch being open when engaged by saidhandle; a second switch having a third and a fourth position; saiddriving means being conditioned for operation in a forward direction tomove said handle to said first position when said second switch is insaid third position and being conditioned for operation in a reversedirection to move said handle to said second position when said secondswitch is in said fourth position; a first control effective to actuatesaid driving means when said second switch is in said third position; asecond control effective to actuate said driving means when said secondswitch is in said fourth position; said first switch being connected inparallel with said second control.

5. A mechanism for the operation of a circuit breaker manual operatinghandle; said mechanism comprising a driving means, a cam, and a couplingmeans; said coupling means forming a first driving connection betweensaid cam and said driving means; said cam being operatively positionedto engage a circuit breaker operating handle; said coupling means beingconstructed to slip when the torque required to drive said cam exceeds apredetermined value; said cam including a first portion and a secondportion spaced from said first portion to form a gap therebetween; saidmechanism being adapted for mounting to a circuit breaker with theoperating handie of the circuit breaker being positioned Within saidgap; a second driving connection interposed between said driving meansand said first driving connection; said second driving means beingselectively disengageable and when disengaged permitting manualoperation of the circuit breaker; said second driving connectioncomprising a polygonal nut biased toward engagement with said drivingmeans to be received by a complementary opening therein.

6. A mechanism for the operation of a circuit breaker manual operatinghandle; said mechanism comprising a driving means, a cam, and a couplingmeans; said coupling means forming a first driving connection betweensaid cam and said driving means; said cam being operatively positionedto engage a circuit breaker operating handle; said coupling means beingconstructed to slip when the torque required to drive said cam exceeds apredetermined value; said cam including a first portion and a secondportion spaced from said first portion to form a gap therebetween; saidmechanism being adapted for mounting to a circuit breaker beingpositioned within said gap; a second driving connection interposed between said driving means and said driving connection; said seconddriving means being selectively disengageable and when disengagedpermitting manual operation of the circuit breaker; said second drivingconnection comprising a polygonal nut biased toward engagement with saiddriving means to be received by a complementary opening therein;selective means extending externally of said mechanism and operable tomove said nut against the force of its bias away from said driving meansto disengage said second driving connection.

7. A mechanism for the operation of a circuit breaker manual operatinghandle; said mechanism comprising a driving means, a cam, and a couplingmeans; said coupling means forming a first driving connection betweensaid cam and said driving means; said cam being operatively positionedto engage a circuit breaker operating handle; said coupling means beingconstructed to slip when the torque required to drive said cam exceeds apredetermined value; said cam including a first portion and a secondportion spaced from said first portion to form a gap therebetween; saidmechanism being adapted for mounting to a circuit breaker beingpositioned within said gap; a second driving connection interposedbetween said driving means and said first driving connection; saidsecond driving means being selectively disengageable and when disengagedpermitting manual operation of the circuit breaker; said second drivingconnection comprising a polygonal nut biased toward engagement with saiddriving means to be received by a complementary opening therein;selective means extending externally of said mechanism and operable tomove said nut against the force of its bias away from said driving meansto disengage said second driving connection; a shaft coaxial with' saiddrum and keyed to said cam; said selective means comprising adepressible sleeve coaxial with said shaft; said sleeve having a firstend thereof in engagement with said nut and a second end adapted forengagement by an external operating crank.

8. A mechanism for the operation of a circuit breaker manual operatinghandle; said mechanism comprising a driving means, a cam, and a couplingmeans; said coupling means forming a first driving connection betweensaid cam and said driving means; said cam being operatively positionedto engage a circuit breaker operating handle; said coupling means beingconstructed to slip when the torque required to drive said cam exceeds apredetermined value; said cam including a first portion and a secondportion spaced from said first portion to form a gap therebetween; saidmechanism being adapted for mounting to a circuit breaker with theoperating handle of the circuit breaker being positioned within saidgap; a second driving connection interposed between said driving meansand said first driving connection; said second driving means beingselectively disengageable and when disengaged permitting manualoperation of the circuit breaker; said second driving connectioncomprising a polygonal nut biased toward engagement with said drivingmeans to be received by a complementary opening therein; selective meansextending externally of said mechanism and operable to move said nutagainst the force of its bias away from said driving means to disengagesaid second driving connection; a shaft coaxial with said drum and keyedto said cam; said selective means comprising a depressible sleevecoaxial with said shaft; said sleeve having a first end thereof inengagement with said nut and a second end adapted for engagement by anexternal operating crank; said shaft having a formation at an endthereof engageable by a complementary formation of said crank when saidsleeve is depressed thereby providing a driving connection between crankand said cam.

9. A mechanism for the operation of a circuit breaker manual operatinghandle; said mechanism comprising a driving means, a cam, and a slipcoupling; forming a first driving connection between said cam and saiddriving means; said cam including a first portion and a second portionspaced from said first portion to form a gap therebetween; saidmechanism being adapted for mounting to a circuit breaker with itsoperating handle being positioned within said gap; a second drivingconnection interposed between said driving means and said first drivingconnection; said second driving means being selectively disengageableand when disengaged permitting manual operation of the circuit breaker;said second driving connection comprising a polygonal nut biased towardengagement with said driving means to be re ceived by a complementaryopening therein, selective means extending externally of said mechanismand operable to move said nut against the force of its bias away fromsaid driving means to disengage said second driving connection; a shaftcoaxial with said drum and keyed to said cam; said selective meanscomprising a depressible sleeve coaxial with said shaft; said sleevehaving a first end thereof in engagement with said nut and a second endadapted for engagement by an external operating crank; said shaft havinga formation at an end thereof engageable by a complementary formation ofsaid crank when said sleeve is depressed thereby providing a drivingconnection between crank and said cam; indicator means carried by saidshaft and positioned externally of said mechanism whereby the positionof said cam may be determined.

10. A mechanism for the operation of a circuit breaker manual operatinghandle; said mechanism comprising a driving means, a cam, and a slipcoupling; forming a first driving connection between said cam and saiddriving means; said cam including a first portion and a second portionspaced from said first portion to form a gap there between; saidmechanism being adapted for mounting to a circuit breaker with theoperating handle of the circuit breaker being positioned within the gap;a second driving connection interposed between said driving means andsaid first driving connection; said second driving means beingselectively disengageable and when disengaged permitting manualoperation of the circuit breaker; said second driving means whendisengaged preventing said driving means from operating the circuitbreaker; said circuit breaker handle being movable between a first and asecond position; said mechanism also including a normally closed firstswitch operatively positioned for engagement by said handle when saidhandle is in said first position; said switch being open when engaged bysaid handle; a second switch having a third and a fourth position; saiddriving means being conditioned for operation in a forward direction tomove said handle to said first position when said second switch is insaid third position and being conditioned for operation in a reversedirection to move said handle to said second position when said secondswitch is in said fourth position; a first control effective to actuatesaid driving means when said second switch is in said third position; asecond control effective to actuate said driving means when said secondswitch is in said fourth position; said first switch being connected inparallel with said second con trol; said clutch means comprising arotatable drum'and engaging means in contact with the peripheral surfaceof said drum and biased toward the center of said drum; said engagingmeans being carried by said cam; said second driving connectioncomprising a polygonal nut biased toward engagement with said drivingmeans to be received by a complementary opening therein; selective meansextending externally of said mechanism and operable to move said nutagainst the force of its bias away from said driving means to disengagesaid second driving connection; a shaft coaxial with said drum and keyedto said cam; said selective means comprising a depressible sleevecoaxial with said shaft; said sleeve having a first end thereof inengagement with said nut and a second end adapted for engagement by anexternal operating crank; said shaft having a formation at an endthereof engageable by a complementary formation of said crank when saidsleeve is depressed thereby providing a driving connection between crankand said cam.

References Cited in the file of this patent UNITED STATES PATENTS620,839 Bernadini et a1. Mar. 7, 1899 2,050,613 Kellogg Aug. 11, 19362,675,835 Kiekhaefer Apr. 20, 1954 2,761,331 Buescher Sept. 4, 1956

